Originally posted by anatech
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Many things will affect the sound. Feedback ratio is a big one,
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-Chris

Hello Chris,

which are the more evident differences in the sound between a very high feedback amp and a very low feedback amp ?
When you say feedback ratio do you mean close loop gain divided by open loop gain?
Which feedback ratio do you think is the optimum?

It's not a joke. An equalizer is the right tool in order to obtain these effects. By moving a few sliders you can instantly make the music dark or brigth, punchy or bassy, forward or recessed, thin or thick, articulate or muddy...

You wont't be able to distinguish whatever little modification you do to an amplifier in a blind test, but you will easily distinguish equalisation.

I did live audio mixing for several years (vocals, guitars, wind), so I had to use equalization and compresion extensively. Some people may seem puzzled at what I say, but it's because they have never done serious listening while mixing and equalising. On the other hand, when you are in a venue mixing for a few hundred people you are forced to do *serious* listening and to create effects in order to make the mix "listenable"

Hi beppe,
Varying the feedback ratio changes many things at once. The ratio you choose depends on the open loop gain and how much closed loop gain you want. There are too many factors to come up with a simple statement.

I have found that as you increase the feedback, at some point the music loses it's "dynamics". This may or may no be the case with some amps. I haven't played with everything (hardly any compared to how many designs there are). There are designers that are far more experienced than I am who could better comment here.

The very best thing you could do is play with a design you are experienced with and vary tail currents, feedback and so many other things. Then once you have the amp stabilized again, have a listen.